v80z Posted October 23, 2006 Share Posted October 23, 2006 Well Itook off the 041 casting stock heads and replaced them with World Prodcut Sportsmen 2s. Out for a open header test drive. Watch the F^(K out. This thing is ready to eat. Of course the lady on the corner had a migraine so I had to hear it from her at the bustop. Anyway I got to go through the normal carb tuning exercise as she is stumbling going to open throttle. 355 sbc .508 lift 250 at 050 so almost a 300 duration. 4 speed 3.90 rear gear. I guess that is all the pertinent data. Inital timing with vacuum is 20 advanced with mechanical ~38 Edlebrock 750 I have the cal kit and procedure. With the stock heads I had it running and making power over the whole range. Now when I step on it It acts as if it isnt getting enough fuel. Smaller enrichment rods? lighter or heavier enrichment rod springs? I did not know what a difference going from a 160 runner with 1.5/1.94 to 200 runner with 1.6/2.02 would nmake but it will require a whole new tune. Being Ignorant sure is interesting!!!! Quote Link to comment Share on other sites More sharing options...
icewtr Posted October 24, 2006 Share Posted October 24, 2006 You need more fuel.. Quote Link to comment Share on other sites More sharing options...
v80z Posted October 24, 2006 Author Share Posted October 24, 2006 icewtr YEah Say you are one of the few running the 3.364 rear gear. Man I would like to get one of those. Where did you find yours. Is it for sale? R200? Want to trade for a welded 3.90? Quote Link to comment Share on other sites More sharing options...
HICKL Posted October 24, 2006 Share Posted October 24, 2006 He V80z, I went from stock heads with minor port and polishing to the sportsman II's and it was way lean. Went up a few jet sizes to feed it. Jeff Quote Link to comment Share on other sites More sharing options...
icewtr Posted October 24, 2006 Share Posted October 24, 2006 icewtr YEah Say you are one of the few running the 3.364 rear gear. Man I would like to get one of those. Where did you find yours. Is it for sale? R200? Want to trade for a welded 3.90? actually mine is the stock 180 that came in the car..... blew appart the spider gears after about a year of taking it to the track.. made my own spool for it seems to work fine just waiting for a shaft to break now ... as for the main question on this one . about the head swap and fuel .. when i did my last motor i changed the heads to a larger port and also the intake .. it was so lean it would not even rev over 4000...... i cheat now i use a wide band to tune .. no more guessing .. i would add some fuel also you may need a larger pump shot on your accelerator pump.. if it is doing the hesitation right off idle Quote Link to comment Share on other sites More sharing options...
v80z Posted October 24, 2006 Author Share Posted October 24, 2006 Well I 1 Went up 2 sizes rich on enrichment rods. 2. adjusted the pump linkage for a bigger shot 3 Went up one size stiffer, more vacuum, on the enrichment springs That may have been the wrong. Waiting for a test rides. Gotta get some exhaust collectors and gaskets. I will let ya know. Quote Link to comment Share on other sites More sharing options...
John Scott Posted October 24, 2006 Share Posted October 24, 2006 So you got the cam, heads, now quit playing with the street carb and get a decent 750 mechanical secondary. You'll have an animal! Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted October 24, 2006 Share Posted October 24, 2006 youll generally need a richer mix and a longer accellerator pump shot/voluum simply because the engines pumping a good deal more airflow, and youll want to get the F/A mix ratio in the 12.7-13.1:1 range Quote Link to comment Share on other sites More sharing options...
v80z Posted November 2, 2006 Author Share Posted November 2, 2006 Well I almost got the edelbrock making power. I am sure there are a few of you that are familiar with them. I bought the calibration kit which gives you several jet and rod options. I studied the lean rich application chart and decided to start 1 step rich for both power and cruise. Nothing. Stumbles and falls. I decided to go to the very extreme step 29 which was at the very right hand top corner of the rich/rich chart. Took it out. OK now we are getting close. Blipped up to 5k rpm in 4th with very little trouble. I still have a Holley 4160 with vac 2ndaries coming. Also I got a 3.364 r200 shipping today should have it soon. God this thing might make it down the front straight before running out of gas. With the 255/50 16s and a 3.364 rear end. Cammed for the high end and a 1:1 4th gear at 6500 rpm gives me around 150 mph. Hoping I dont sacrifice too much grunt for getting out of the corners. Quote Link to comment Share on other sites More sharing options...
Paz8 Posted November 2, 2006 Share Posted November 2, 2006 What heat range are the spark plugs and how do they look? Had same problem, stumble off idle, went one heat range hotter on plugs, stumble gone, latter when the carbs tuned and everything else is set up you can probably go back to a colder heat range. I'm using an O2 sensor and digital meter to tune the mixture on a 750 Holley, warm up the car connect the meter inside and drive off, read the meter while cruising about 60MPH works really well. I went DOWN from #72 primary jets to #68 and the sensor reads .620 volts (standard sensor 0- 1 volt range) I didn't know how this would work out so I didn't spring for a wide band sensor. More fuel is not allways the answer. Quote Link to comment Share on other sites More sharing options...
Guest rucus01 Posted November 6, 2006 Share Posted November 6, 2006 What torque convertor do you have in it? With that much cam your gonna need a pretty high stall or it will bog when you get on it. That is problem one. The second problem is the edelbrock street carbs only really work on cams with duration at .050 up to 220. With 250 duration at 0.050 you will be into the transfer circuit once you set your idle up where you need it. When you step on it you wont get the extra gas quickly from the transfer cirtcuit that you will need since you will be drawing your idle gas from the transfer. The solutions are to run your idle very rich (will foul plugs) or to drill holes in the butterflys so that you can have them closed further, or to get a carb that is designed for that big a cam. (I had a similar problem running that exact same carb with a big cam as well) Quote Link to comment Share on other sites More sharing options...
v80z Posted November 7, 2006 Author Share Posted November 7, 2006 Thanks Fellas Well I got a holley 4160 750 cfm vac 2ndaries coming. I run a manual tranny. I went all the way to the rich end of the cal chart/kit. IT runs decent on the primaries but no where near as well as when you get into the 2ndaries. I am gonna put the holley on and go from there. BTW any V8 Zs running a 3.364 rear end? Impressions? Thanks Quote Link to comment Share on other sites More sharing options...
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